Ok, thanks for the response. The reason I asked how he was doing in school was because schools typically do more than talk to the kids. If he is also having problems in school (and has an experienced teacher) than this is indeed more of a problem and the school can help.
Of course, if this is only happening at home - its still a heck of a problem for you (or you would not have posted). So a couple of ideas. Get the book, "SOS Help for Parents," by Lynn Clark and follow it as closely as possible.
Second, go to this link and read the suggestions by specialmom. They will work. I would also check into the books I suggested in my last post on this site. The link is
http://www.medhelp.org/posts/Child-Behavior/-4-year-olds-crazy-behavior/show/1717969.
Particularly, note what I say about how long it takes for behavioral modification to work and how important consistency is. This is something that will work. It just doesn't happen overnight. Best wishes.